Unless it is an Iridium handset to Iridium handset call, it will always be routed to one of Iridium's ground stations: - Arizona - Hawaii (Military only) - Rus

Unless it is an Iridium handset to Iridium handset call, it will always be routed to one of Iridium's ground stations: - Arizona - Hawaii (Military only) - Russia and then it is routed through the fibre backbone. With the SpaceX proposal there will be more ground egress points, so it will be able to get closer to the destination before grounding.